18 (MRP) Introduction.MRPObjectives. Introduction.MRPObjectives. Functionsservedby servedby MRP Masterproduc Masterproductionsc tionschedule hedule(MPS (MPS MR outp output uts. s. es
Mana Manage geme ment nt in or atio atio ro RP ~_Lo ~_Lo Sizi Sizing ng cons cons de at ons. ons. Capac Ca pacit it requ requir irem emen ents ts plan planni ning ng (CRP) (CRP)
Manu Manu actu acturi ring ng
18.1 18.1 INTR INTROD ODUC UCTI TION ON
syst syst
th us th depe depend nd nc rela relati tion onsh ship ip to pl an ontr ontrol ol ma manu nu actu acturi ring ng op rati ration ons. s. RP is tech techni niqu qu of work workin in back backwa ward rd from from th sche schedu dule le qu ntit ntitie ie an need need date date fo nd te pe st od ti he le th ir he du ti le ni ne ts th he th ou th ik ly il og se th ke po in nf io
id hl orde orders rs an purc purcha hase se orde orders rs
li
ic
th
orit orit
sche schedu dule le requ requir irem emen ents. ts. of ol effe effect ctive ive ma manu nufa fact ctur uring ing contr control. ol.
ie
in
8.
ne
in
oi
ss
ompo ompone nent nt qu ntit ntitie ies, s, timi timing ng wh prod produc ucti tion on acti activi viti ti info inform rmat atio io
du il
he
in
to y.
th
te
/c
they they re need needed ed av ilab ilabil ilit itie ie an proc procur urem em nt an acti action on
by putt puttin in du date date on usto usto er jo orde orders rs
abou abou like likely ly deli delive very ry time time to pros prospe pect ctiv iv cust custom omer ers. s. ie lo 237
tr
and
INDUSTRIAL ENGINEERIN
238
AN
PRODUCTION MANAGEMENT
henc help to achiev uninterrupte flow of material throug th production line This increase th ef icienc prod ctio system
materials/components. need date fo each component. plans. Th followin question ar addresse in MR processing Provided by Master roduct on Schedu BO ow many availabl in each futu
Inventor
pe iod.
status file
Difference in required an availabl future period Planne
orde releas
be availabl when needed
18.4 MR depend nc item.
ERMINOLOGY he
gr
to whic th de an
or ne item is ss iate wi
de an fo
noth
meet th planne output levels
period minu amount availabl from th previous period 8. qu re ents explosion: br \kin do of (exp od ng parent te part that ca be individually planne an scheduled. of or er th
re iv
have ee plac d.
on schedule ft
th le
an receivin th ma~erials.
im
ffset.
into om on nt
MATERIAL REQUIREMEN
239
PLANNING (MRP
18.5. MR SYSTEM
MASTER PRODUCTIO ~CHEDULE (MPS
Inventory Statu File
Materials Requiremen Plannin (MRP Processing logic
Order Release Requirements (Order to be placed now)
Orders Rescheduling
Bill of Material (HOM)
Planne Order (Future)
Fig. 18.1: MRPsystem.
I'
ts to
te
ti
to
tatu
requirements orde rescheduling an planne orders
I~
te requ reme ts Most system th make master schedule ca be satisfied.
ru
simulate
Inventor Status File Every inventory ite beingplannedmust hav an inventorystatusfil which gives complete re times, safety stoc levels an scra allowances ic lly, th ob'o th in entory tatu file is
ee
at
bout he pr je te
se nd receipts
of eachitem an to determin th amounto inventor that wil be availablein eac tim bucket projectedavailableinventoryis not adequateto meettherequiremen in period the MR
pr gramme w.ll reco mend th
it it
be or er d.
8i11of Material (80M To scheduletheproductionof an end product,the MRPsystemmustplanfor all the materials
provide this information.BOM file identifie each component by unique part numberand help processingby proces which 'explodes' end itemrequirementsinto componentrequirements. Thu BOM identifie ho each end produc is manufactured,specifyingall subcomponent
240
INDUSTRIAL ENGINEERING AN
PRODUCTION MANAGEMENT
performing th buil up sequen e. hi informatio is obtained from produc design do uments
components.
18.2. ve 0'
od t)
Components Leve (1 Components Leve (2 st
wo
it
Band
product requires on unit of omponent in F. Th componen turn requires on ni of comp nent fa ro ar number fo it identifi ation. he eparat id ntifications nabl co pute to find an parent
If
re he produc stru ture tree fora thre dr we file abin 18.3. Leve '0
drawer file cabinet Part o. 00
Leve '1
Leve '2
Leve '3
withou fastener is represente in Fig.
1( week
MATERIAL REQUIREMEN
241
PLANNING (MRP
Number
Description File cabine
001
Case assembly Lock Drawer assembly 1001
Case assembly Drawer slides Formed case
1003
Drawer assembly Formed drawer Handle Suppor roller Formed case
2002
Shee stee Formed drawer
2003
Shee Stee
18.6. MRP.OUTPUTS hous production shops. variet re orts ca be generate from th informatio ma
availa le by an MR Progra
TO MP Planners ro MP Researchin informatio fo open or er (due to cancellation dela s, shortages) To Purchasing an Production ep re rd rs Plan ed rder releases To capacit Requirement Planning rd fo fo To Managemen Perfor ance meas re en (vendors cost forecast accuracy
18.7 MR
OGIC
pr duct struct re an fo each time erio (t picall ab hipments must be planne (pla ne re re ca recorded in inventor statuS file Net reqUIrements
an rder releases
reqUIremen
ne week in th planni
orizon ow many
ei rd that al material arrive when eede en re nh
242
INDUSTRIAL ENGINEERIN
rder el as
'. :' I.
ar planne fo co ponent
AN
im ph se
PRODUCTION MANAGEMENT
an er (u in
ea time at
ro
planne orde receipt. When the.orders ar actually issued to vendor or shop th planne receip become th schedule receipt.
18.8. MANAGEMENT INFORMATIO FROM MR lARPoutpu includes report as s~ow in Fig. 18.4fo on component. Th detailed identification Th report show that
weeks requirements ee he
ne equirement
sh ul
la
re eive 35 un ts
ou
eeks nd 00 un ts
This report clearl identifies th procuremen action required to keep production on schedule ny hang nd em de an th ime, odific tion in he il dictat or espond .n adjustment of lowe leve requirements WEEK
J
2
3
4
Gross requirements
5
6
7
8
400
500
350
500
Scheduled receipts
Availablefor next period
50
50
Net requirements Planne
Orde receipts
Planne
Orde releases
350-
--
Fig 18.4 An MA report fo
---
350
-500
500-
ne item
18.9. LO SIZIN CONSIDERATION Th released orders should specif discrete lo size fo purchasing or manufacturing. Th variou lo sizing techniques availabl ar give below: ECONOMIC ORDE
QUANTITY (EOQ).
carrying
he la ning horizon.
derive
os
du in
part pe io I)umbe an us th nu be as
time (e.g.,
crea io
or um la in
equireme ts
243
MATERIAL REQUIREMENT PLANNING (MRP)
Pr blem 1: ompl te th material re uirement st
la fo
it
show belo
Th it
as
WEEK
Orde Quantity 70 Lead time Safety stoc 40
10
Projected requirement Receipts
70
I-
Planne orde release
Solution. WEEK
Orde Quantity
70
Lea tim
Safety stoc
I
40
2
3
4
5
6
ProjeLted requirement
25
Receipts
100 .Jff Planne orde release
25'
70
70
70
Problem
sh ft asse bl an
ne wheel. Fo shaf re Part
ssembl
rder uantit es lead ti es an invent ries on Lead time
Orde Qty.
to
200
Housings 400
Shaf assembly
440 100
Apar from th
Solution:
bove requir ment
st
noth
80 shafts ss mbly re uire fo anothe
sc ab
18 1:
nd item
st
Schedu
Week Nos. Requirement"
80
120
50
ustome
244
INDUSTRIAL ENGINEERIN Tabl
18.2 Components an
AN
PRODUCTION MANAGEMENT
Subcomponent
Material
Plan
Component Material Plan-Housing WEEK
'.
:1
Order Quantit Lead time
600 we
l'
Projected requirement
:; I,
160
Receipts
240
240
200
600 40
r640
640
400
400
Planne orde release
160/
160
560 40
340
240
Component Material Plan-Shaft WEEK
Orde Quantity Lead time
400
Projected requirement
180*
Receipts /' 360
en of period (440
360
340
360
c.----
Plannedorder t: release
.::::-- j..- 60
.-<1'
Sub-componen M'teria Plan-Wheel WEEK
Orde Quantit Lead time
800
3)
Projected requ'irement ',Receipts
400 400 100
en of period(100) Plannedorder
500 300
100
500
500
release
Requirementfrom anothe product. nent
ucts io
ow
ui ials
lcul
ts it
ho in
od
uately
lo
do week
MATERIAL REQUIREMEN
245
PLANNING (MRP
Each unit of produc requir
on sh ft ssembl an 18 shaf
ssembl ar need
fo anothe
wi
su
Si
18.10. MANUFACTURIN RESOURCE PLANNING (MRP-II) Manufacturin Resource Planning (MRP-II) is an integrated informatio system that synchronis al aspect of th business MRP-II system coordinate sales, purchasing anuf ctur ng financ
s. (i) Produc pl nnin func ions wh ch take plac at th
op
wh anag ment le el
(ii) Operationsplanninghandledby staff units. (iii) Operations contro function conducte by manufacturin line an staf supervisors. On resour es co pletenes of resource om it ents an th qual ty of performanc in arry ng ou s. se nth se se si th latest operatin data Pwn Th proces (a show in figure involv developing produc io pl ro th business plan Manufacturing (Material capacity productio schedule
Inventory
.1
Engineering Productio Process design MRP
.[
Detailed capacity plan
Marketing
Financing
Accounting Fig. 18.5
I-An
sy te
for planning and control.
INDUSTRIAL ENGINEERIN
246
production depart en he is expected ep
AN
roduce at th co
specific products to be buil Then th capacity availabl
PRODUCTION MANAGEMENT
itte le els, he sa es de ar eq al
en
roughl adequate If not, either ma te
ateria re uire en an priority sche ules fo roduction. he an analys of de aile capa it requ reme etermine whethe capaci is ufficien at each work ce tr during schedule ti sc edul is
et
18.11. CAPACITY REQUIREMENTS PLANNING (CRP apacit is measur he productive capa il ty of faci it er unit of ti e. apac ty ec sion begi with th initia facility layout an extend to aggregat planning master scheduling capacity requirements planning. ro
ec
em
plan."
ed
at
at
ca ci
correctiv actions. together MR an CR programmes translat th master schedule to requirements fo components run. Pl
4.
er
ea
er
Changeswhichmodifycapacity give alternativeroutingsor alte plannedorders.
otherwise indicated
an actually designatin th capacity fo specific orders
PS
MATERIAL REQUIREMEN
247
PLANNING (MRP
Revise
Product Structurefile
Routin
file
Productio standard file
Dat about scheduled receipts
No
Yes
Yes Adjust capacity
Vendors
Shop
(1987).
Operation Management, Pr du ti
Ne
System-Plannin
it An lysi mi Control,
York (1987) Productio and Operation Management, 5t Edition, Mc
York, (1993).
Materials Requirement Plann.ing McGraw Hill Ne et at., Manufact ri
Planning an Contro
Irwin, (1992) REVIE
QUESTIONS
in in
io
Distin uish etween pl nn
re eipt nd sche uled receipt.
ystems
Hill Comp~ny, Ne
York (1975) rd diti n, Home oo III,
INDUSTRIAL ENGINEERIN
248'
(a) Bill of Material (BOM (b) Master Production Schedule (MPS (c) Product Structure
,~
i"
(d) MR planning horizo (e) CRP
.~
(g)
.~~ ~-
.-
'3>~
1i
..J.
c>i-e: ~.. .;;.
Manufacturin resource planning.
AN
PRODUCTION MANAGEMENT
